1. Field of the Invention
The present invention relates to telecommunications networks and in particular to telephone networks including facilities for carrying out, telemetry or remote control functions.
2. Related Art
The cost to utility companies, such as gas, electricity and water suppliers, of manually reading meters is substantial. Consequently, meters are read infrequently and householders frequently receive estimated accounts rather than those based on actual consumption. Further difficulty can arise where meter readers are unable to obtain access.
Thus, remote meter reading is desirable although the high capital cost of installing a communications network specifically to read utility meters, particularly retrospectively, may not be justified. In the past, some remote controlled operations have been carried out using dedicated telephone links through public switched telephone networks. However, such usage of dedicated telephone numbers for use say once a month could not be justified.
Accordingly proposals have been put forward by the present applicant and others to use existing telephone network connections to customer premises to carry out various remote control and/or telemetry tasks. One problem with such proposals is that such usage of the telephone network could adversely affect network telephony traffic or other services offered over the network. For example there may be regulatory requirements regarding availability for telephone calls. Also, if there are tariff differentials between network uses for different purposes, a network operator will wish to give priority to the network use which generates the higher revenue. Also calls such as telemetry calls will normally be less time sensitive and therefore of lower priority than, say, a telephone call which may relate to potentially life-threatening circumstances.